Method for producing a camera module

ABSTRACT

A method for joining a camera module, which includes a base plate on which an image sensor is situated, and an objective holder in which an objective of the camera module is accommodated. The base plate and the objective holder are aligned relative to each other in a connection region and a connecting pin is guided through a recess of the base plate and/or the objective holder so that the connecting pin protrudes on the outside, and the at least one free end of the connecting pin is widened by a forming die using a radially acting deformation force such that the base plate and the objective holder are pressed against each other.

CROSS REFERENCE

The present application is a divisional application of U.S. applicationSer. No. 17/014,415 filed Sep. 8, 2020, which claims the benefit under35 U.S.C. § 119 of German Patent Application No. DE 102019214206.0 filedon Sep. 18, 2019, and German Patent Application No. DE 102020202784.6filed on Mar. 4, 2020, which are all expressly incorporated herein byreference in their entireties.

FIELD

The present invention relates to a camera module and to a method forproducing such a camera module.

BACKGROUND INFORMATION

In camera modules, the interface between the circuit board of the imagesensor and the objective holder/housing is frequently connected bybonding, screwing or caulking. Sometimes methods such as welding orsoldering are used as well in order to produce a substance-to-substancebond.

European Patent No. EP 3,280,127 A1 describes a camera system formeasuring applications, which has an objective carrier and an imagesensor situated on the circuit board. The circuit board can be connectedto the objective holder using different fasteners. For example, screwed,riveted or bolted connections are described in this case. In the sameway, the circuit board and the objective holder can be connected to eachother via a welded, soldered or a bonded connection.

SUMMARY

An object of the present invention it to produce a space-savingconnection between the circuit board and the objective holder/housingthat provides excellent thermal conduction and holding properties. Thisobjective may be achieved in accordance with example embodiments of thepresent invention. Preferred embodiments of the present invention aredescribed herein.

The present invention provides a method for joining/assembling a cameramodule, which includes a base plate on which an image sensor issituated, and an objective holder in which an objective of the cameramodule is accommodated, the base plate and the objective holder beingaligned relative to each other in a connection region, and a connectingpin being guided through a recess of the base plate and/or the objectiveholder so that the connecting pin protrudes on the outside. The at leastone free end of the connecting pin is widened by a forming die using aradially acting deformation force such that the base plate and theobjective holder are pressed against each other.

A connecting pin is understood as a pin-shaped element, which extendsthrough a corresponding recess of the base plate or the objectiveholder, which is preferably developed as a bore. The connecting pinprojects beyond an outer side of the component through whose recess theconnecting pin passes.

The connecting pin is able to be developed as a separate component,which extends through a corresponding recess of the base plate and theobjective holder. The connecting pin would therefore have two free ends.In the same way, however, the connecting pin may also be formed directlyby the objective holder or the base plate or be fixedly connected to itso that the connecting element has only one free end.

A plastic change in shape of the free end, which consists of wideningthis end, is brought about with the aid of the forming die. The free endis widened in such a way that the outer dimensions of the free end arelarger than the outer dimensions of the recess. This causes the baseplate and/or the objective holder to be pushed in a direction counter tothe free end toward the center of the connecting pin. An axial holdingforce is correspondingly produced, which presses the base plate and theobjective holder against each other.

The widening fills a gap between the connecting pin and the recess sothat a positive connection is produced with the aid of the connectingpin. An axial contact pressure is thus applied in a connection region inwhich the base plate and the objective holder rest against each other.

In comparison with welding, for example, such a connection between thebase plate and the objective holder is able to be produced faster andmore economically. Moreover, no additional screw-in depth for therequired thread length has to be provided as needs to be done in thecase of a screwed connection. The wall thickness of the base plateand/or the objective holder may be correspondingly reduced. Such acamera module may therefore have a smaller design, which translates intospace savings. This is advantageous in particular because of the tightinstallation situation of such a camera module.

The advantage of conventional caulking over a rivet head is that thereis no need to bridge the base plate to allow for pretensioning of thebase plate and the objective holder. This avoids potential damage to theimage sensor. In addition, such a connection requires less space so thatmore surface is available on the circuit board for electricalcomponents/layout.

In contrast to a bonded connection, a bonding layer between the baseplate and the objective holder is not required either. Such a bondinglayer reduces the thermal conduction between the base plate and theobjective holder. In contrast, the base plate and the objective holderhave direct planar contact with each other according to the presentinvention so that the thermal conduction is considerably improved. Byconnecting the base plate and the objective holder with the aid of theconnecting pin, a space-optimized camera module is produced, whichoffers high stability and excellent thermal conduction.

In one preferred embodiment of the present invention, prior to thejoining, the connecting pin is developed as a positioning pin of theobjective holder or the base plate. The connecting pin is thuspermanently provided so that no additional joining parts are necessary.In addition, an exact positioning of the base plate and the objectiveholder is able to take place via the connecting pin. The connecting pinthus has multiple functions so that corresponding positioning means orelements are able to be dispensed with.

In a further preferred embodiment of the present invention, theconnecting pin is hollowed out on the inside at the free end prior tothe widening. ‘Hollowed out’ means that only a desired wall thickness ofan outer edge remains in the region of the free end. In a cylindricalconnecting pin, such a cavity is preferably produced by a bore so that ahollow-cylindrical region is formed at the free end.

The hollowing out has the advantage that a corresponding widening isable to be produced using a smaller pressure force of the forming die.This avoids damage to the components. In addition, such a widening isthereby easier to produce.

Prior to the widening of the connecting pin, an inner bead is formed inthe hollowed-out free end of the connecting pin so that an outer bead isdeveloped by the widening. An inner bead in the sense of the presentinvention is understood as a thickening that is situated in thehollowed-out free end and extends inwardly toward a center of theconnecting pin. The inner bead is raised in relation to the corediameter. The inner bead is preferably situated at the level of an outerside of the element to be fastened. Accordingly, an outer bead is athickening which protrudes in an external region of the connecting pin.This inner bead/ring segment is able to be produced by introducing abore from the oppositely situated side of the objective holder.

By introducing the forming die into the region of the hollowed-out freeend, a greater radial deformation force is generated in the region ofthe inner bead, which means that the material in this region is moreheavily pushed in the outward direction in comparison with the rest ofthe widened region. An outer bead at the level of the component to befastened is formed in a corresponding manner. The thereby developingposition of the outer bead is consequently able to be specified by thepositioning of the inner bead. This improves the attachment of the baseplate to the lens carrier.

The connecting pin is advantageously widened at the free end with theaid of a conical forming die. A conical forming die is understood as atool that is conical at least in a frontmost region which acts on thefree end. The forming die may be developed as a conical die or as a diein the shape of a truncated cone. Because of the conical shape of theforming die, the free end is able to be steadily widened. Moreover, thepress force is reduced.

In one preferred further development of the present invention, theconical forming die has an obtuse angle so that apart from a radialwidening deformation force, an axial force is additionally applied tothe base plate via the connecting pin, which improves the attachment ofthe base plate to the objective holder.

In an advantageous further development of the present invention, towiden the connecting pin via the forming die, a conical insertionelement is mounted on the free end of the connecting pin, which remainsin the free end of the connecting pin after the widening. The connectingpin is both widened and the widening is protected from returning to itsoriginal shape because of the insertion element, which is permanentlyprovided in the free end after the widening. The widening isconsequently able to be provided on a permanent basis. The surface ofthis insertion element could be developed in such a way that the surfacehas a defined profile, e.g., has grooves or a defined roughness. Thus,the insertion element is additionally connected in a positive manner.

According to an alternative embodiment of the present invention, theconnecting pin is widened at the free end with the aid of a cylindricalforming die. The part of the cylindrical forming die that penetrates thefree end of the connecting pin has a smaller diameter and a shorterlength than the connecting pin. In addition, this part is fastened to aregion whose outer dimensions are considerably greater than the diameterof the connecting pin. Because of the widening, this region isadditionally able to be deformed such that the connecting pin exerts anaxial force on the base plate, which fastens it in place. The free endmay thus be widened and an axial force be simultaneously applied in thesame working step.

According to another advantageous exemplary embodiment of the presentinvention, the connecting pin is widened at the free end by a formingdie provided with a segmented outer contour. The outer contour is thusnot developed as a body that forms the entire outer contour. Instead,the forming die has an outer contour that is made up of a number ofsegments. The forming die therefore does not possess this outer contourbetween adjacent segments. The segments advantageously extend radiallyfrom a center and in the outward direction. Four segments are preferablyprovided, which are disposed in the pattern of a cross.

Such a segmented outer contour offers the advantage that material isable to be saved on account of the segment-shaped development of theforming die. In addition, the base plate is subjected to an axial forcevia the connecting pin in essence in the regions in which the formingdie is provided with segments. This makes it possible to reduce theaxial force of the base plate. The deformation force of the forming dieis lower as well. Moreover, excess material is able to be pushed intothe region between the segments.

The connecting pin is advantageously widened at the free end by aforming die having a deflection contour. The deflection contour forms anegative form of the developed end of the connecting pin after thedeformation. The deflection contour includes at least one part forwidening the connecting pin. This part preferably has a conicaldevelopment. In the same way, this part may have a cylindricaldevelopment or be developed with segments. Through the deflectioncontour, the free end is able to be given a defined development. Becauseof the developed shape of the free end, the axial force is adaptable.

In addition, the present invention provides a camera module which isproduced according to the present method. The camera module includes abase plate on which an image sensor is situated, and an objective holderin which an objective of the camera module is accommodated. In addition,the camera module includes a connecting pin, which extends through thebase plate and/or the objective holder in a connection region, the atleast one free end of the connecting pin being radially widened so thatthe base plate and the objective holder are pressed against each other.Such a camera module offers the above-described advantages.

In one advantageous embodiment of the present invention, the free end ofthe connecting pin has a conical outer contour. Via the conical outercontour, a uniform axial holding force is able to be applied in arecess, preferably developed in the form of a bore.

According to a useful embodiment of the present invention, an insertionelement is situated in the widened free end of the connecting pin. Theinsertion element is preferably developed from a metallic material orfrom plastic. The use of such an insertion elements achieves theabove-described advantages.

The free end of the connecting pin preferably has a toroidal outercontour, which rests on the base plate on the face side.

The toroidal outer contour has an outer diameter which is greater thanthe recess of the base plate through which the connecting pin protrudes.As a result, the base plate is simultaneously fixed in place via theconnecting pin. In addition, the toroidal outer contour exerts an axialforce on the base plate by which better fastening is achievable.

In one advantageous further development of the present invention, thefree end of the connecting pin is provided with a plurality ofgroove-type indentations. The groove-type indentations are preferablydeveloped in the form of a cross so that the free end of the connectingpin has the cross-slotted contour.

In addition, the present invention also provides a camera system whichincludes such a camera module. Such a camera system may achieve theabove-mentioned advantages.

Exemplary embodiments of the present invention are shown in the figuresand described in greater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a camera module having connecting pins according to a firstexemplary embodiment of the present invention.

FIG. 2 shows method steps for widening the connecting pins according tothe first exemplary embodiment of the present invention.

FIG. 3 shows method steps for widening the connecting pins according toa second exemplary embodiment of the present invention.

FIG. 4 shows method steps for widening the connecting pins according toa third exemplary embodiment of the present invention.

FIG. 5 shows method steps for widening the connecting pins according toa fourth exemplary embodiment of the present invention.

FIG. 6 shows method steps for widening the connecting pins according toa fifth exemplary embodiment of the present invention.

FIG. 7 shows method steps for widening the connecting pins according toa sixth exemplary embodiment of the present invention.

FIG. 8 shows method steps for widening the connecting pins according toa seventh exemplary embodiment of the present invention.

FIG. 9 shows method steps for widening the connecting pins according toan eighth exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 shows a camera module 10 having connecting pins 14 according to afirst exemplary embodiment. Camera module 10 includes an objectiveholder 18 in which an objective 26 having a lens 30 is accommodated in acutout 22. Objective 26 is fastened to objective holder 18 with the aidof a bond 34, which is applied between objective holder 18 and objective26.

Camera module 10 additionally includes a base plate 38, which restsagainst objective holder 18 in a connection region 42 in a planarmanner. For the positioning of base plate 38 relative to objectiveholder 18, connecting pins 14 are developed as positioning pins ofobjective holder 18 in this exemplary embodiment. Connecting pins 14engage with corresponding recesses 44 of base plate 38. An image sensor50, which is connected to base plate 38, is situated on base plate 38.Image sensor 50 is disposed in alignment with objective 26.

In the exemplary embodiment shown in FIG. 1 , connecting pins 14 aredeveloped to be hollow on the inside by drilling them open so that ahollowed-out region 54 is created. In connecting pins 14 shown in thisfigure, a free end 58 of these connecting pins 14 protrudes beyond baseplate 38. Free end 58 of connecting pin 14 shown on the right side ofthe camera module is additionally widened and has a conical outercontour. Via this outer contour, base plate 38 and objective holder 18are pressed against each other. In contrast, free end 58 of connectingpin 14 on the left side of the camera module has not yet been widened sothat base plate 38 is not sufficiently attached there.

FIG. 2 shows, from left to right, the method steps for wideningconnecting pins 14 according to the first exemplary embodiment. For thispurpose, after connecting pin 14 has been hollowed out and base plate 38has been positioned on connecting pins 14 developed as positioning pins,a conically shaped forming die 62, which is developed in the form of atruncated cone in this instance, is applied to free end 58. This conicalforming die 62 is then introduced into the hollowed-out region using apress force F_(P) so that the free end is widened by a radially actingdeformation force F_(U) until sufficient contact pressure is presentbetween base plate 38 and objective holder 18.

The method steps for widening connecting pins 14 according to a secondexemplary embodiment are shown in FIG. 3 . In contrast to the exemplaryembodiment of FIG. 2 , connecting pin 14 has not been hollowed out inadvance. A conical forming die 62 is therefore applied to free end 58 ofconnecting pin 14 in the center in this exemplary embodiment. Thematerial is widened via the applied press force F_(P) so that an imprint66 of forming die 62 is developed on the free end 58 of connecting pin14. Here, too, forming die 62 is pressed onto connecting pin 14 untilsufficient contact pressure has been established between base plate 38and objective holder 18.

FIG. 4 shows the method steps for widening connecting pins 14 accordingto a third exemplary embodiment. This exemplary embodiment differs fromthe exemplary embodiment shown in FIG. 2 insofar as forming die 62 has aconical insertion element 70 by which connecting pin 14 is widened.However, after the widening, this insertion element 70 is not pulled outagain together with forming die 62. Instead, insertion element 70remains in connecting pin 14 and thereby ensures permanent widening.

In FIG. 5 , the method steps for widening connecting pins 14 areillustrated according to a fourth exemplary embodiment. In thisexemplary embodiment, an inner bead 74 is developed in addition tohollowed-out region 54. This inner bead 74 is disposed in an axialregion of connecting pin 14, which is at a level of an outer side ofbase plate 38. To form a widening, forming die 62 is introduced intohollowed-out region 54. Forming die 62 has a conical development only ina frontal region. The diameter of forming die 62 corresponds at most tothe inner diameter of hollowed-out region 54 without inner bead 74.Because of the insertion of forming die 62 using press force F_(P),inner bead 74 is pressed in the outward direction beyond base plate 38,which results in the creation of an outer bead 78. Via outer bead 78,base plate 38 is pressed against objective holder 18.

The method steps for widening connecting pins 14 according to a fifthexemplary embodiment are shown in FIG. 6 . This exemplary embodimentdiffers from the exemplary embodiment shown in FIGS. 2 and 3 in thatconical forming die 62 has an obtuse angle. Forming die 62 projects fromconnecting pin 14 on the outside. In this particular exemplaryembodiment, connecting pin 14 may be developed from a solid material andalso be hollow on the inside. Forming die 62 is applied to free end 58so that it is widened. Because of the obtuse angle of forming die 62,free end 58 is additionally pressed against base plate 38 in an axialdirection by an axial force F_(A) so that a toroidal outer bead 78 iscreated, which rests against base plate 38 on the face side.

FIG. 7 illustrates the method steps for widening connecting pins 14according to a sixth exemplary embodiment. In this exemplary embodimentas well, a connecting pin 14 may be made from a solid material and alsobe a connecting pin 14 which is hollow on the inside. In this particularexemplary embodiment, forming die 62 has a cylindrical shape. A firstsubregion 82 of forming die 62 has a smaller outer diameter than theadjoining second subregion 86. The outer diameter of first subregion 82is smaller than a diameter of connecting pin 14 while the outer diameterof second subregion 86 is greater than connecting pin 14.

An axial length of first subregion 82 of forming die 62 is smaller thanthe length of connecting pin 14 so that during the deformation step,first subregion 82 of forming die 62 centrally penetrates free end 58and causes it to widen. In addition, second subregion 86 rests againstfree end 58 of connecting pin 14 on the face side. This not only widensconnecting pin 14 but also presses connecting pin 14 against base plate38 with an axial force F_(A), thereby forming a flat, toroidal outercontour is.

FIG. 8 shows method steps for widening connecting pins 14 according to aseventh exemplary embodiment. This exemplary embodiment differs from theexemplary embodiment illustrated in FIG. 6 in that forming die 62 has anouter contour in the form of a truncated cone, which is made up of aplurality of segments 90, segments 90 being positioned in the form of across. This outer contour also has an obtuse angle. During thedeformation step, these segments 90 of forming die 62 are acting on freeend 58 of connecting pin 14 so that it is both widened and axiallypressed against base plate 38. Because of segments 90, free end 58 hasgroove-type indentations 94.

FIG. 9 illustrates method steps for widening connecting pins 14according to an eighth exemplary embodiment. In this exemplaryembodiment forming die 62 has a deflection contour 96 on the inside,which has an axially symmetrical development. Deflection contour 96includes a conical part 98 in the center by which free end 58 isinitially widened. Radially with respect to the edges of forming die 62,deflection contour 96 has a bow-shaped development so that the widenedpart of connecting pin 14 is deformed in accordance with this contouralong the deflection contour in the direction of the edges of deflectioncontour 96.

As a consequence, free end 58 of connecting pin 14 is developed in theform of a toroidal outer contour in this exemplary embodiment, whichexerts an axial force F_(A) on base plate 38.

In one exemplary embodiment, which is not shown, conical part 98 mayalso be developed in the form of a cylinder or may include segments 90.

What is claimed is:
 1. A camera module, comprising: a base plate onwhich an image sensor is situated; an objective holder in which anobjective of the camera module is accommodated; and a connecting pinwhich extends through the base plate and/or the objective holder in aconnection region, at least one free end of the connecting pin beingradially widened so that the base plate and the objective holder arepressed against each other.
 2. The camera module as recited in claim 1,wherein the connecting pin is radially widened by a forming die using aradially acting deformation force.
 3. The camera module as recited inclaim 1, wherein the free end of the connecting pin has a conical outercontour.
 4. The camera module as recited claim 1, wherein an insertionelement is situated in the widened free end of the connecting pin. 5.The camera module as recited in claim 1, wherein the free end of theconnecting pin has a toroidal outer contour, which rests on the baseplate at the front end.
 6. The camera module as recited in claim 1,wherein the free end of the connecting pin has a plurality ofgroove-shaped indentations.
 7. A camera system, comprising: a cameramodule, including: a base plate on which an image sensor is situated, anobjective holder in which an objective of the camera module isaccommodated, and a connecting pin which extends through the base plateand/or the objective holder in a connection region; wherein at least onefree end of the connecting pin is radially widened so that the baseplate and the objective holder are pressed against each other.